Many Clinical Trials Are Not Listed in Data-Sharing Repository

WEDNESDAY, July 6, 2016 (HealthDay News) — Only about half of trials registered at ClinicalTrials.gov are listed in the largest data-sharing repository, according to a research letter published online June 28 in the Journal of the American Medical Association.

Isabelle Boutron, M.D., Ph.D., from Paris Descartes University in France, and colleagues examined the proportion of randomized clinical trials (RCTs) registered at ClinicalTrials.gov that were listed on the Clinical Study Data Request (CSDR) data-sharing repository website. ClinicalTrials.gov was searched using the names of four sponsors; data were downloaded for all studies listed at CSDR for the same sponsors.

The researchers found that there were 966 RCTs (462,751 participants) for the 61 targeted drugs from the four sponsors; 53 percent of these trials (with 74 percent of participants) were listed at CSDR. The availability of each document at CSDR varied from 83 to 99 percent; 40 percent of RCTs reported that all documents were available. The proportion of registered trials listed on CSDR ranged from 33 percent at Roche to 66 percent at GlaxoSmithKline (GSK); the proportion of trials with all information available varied from 24 percent at Boehringer Ingelheim to 58 percent at GSK.

“Despite a delay of 18 months since the completion of drug trials by the company sponsor, only 53 percent of the RCTs from the four sponsors registered at ClinicalTrials.gov were listed at CSDR, with differences between sponsors,” the authors write.